Yes it can be considered

Mother have become sole owner on the basis of release deed.

now can the Release Deed be considered as "Title Deed". -- chain of document and title deed for your share transferred to her. 

You need original chain of documents of title 

once release deed is executed duly stamped and registered your mother would be absolute owner of property 

release deed  Is one of documents of title to property 

if the release deed is for a consideration and is stamped and registered, then it will be taken as a title deed for the share which has been released in favour of the releasee father 

Instead of that you should have performed relinquish deed.

- No, a Released deed cannot be considered as Title deed , as it is only a proof of leave respective share in the name of other .

- After the death of your mother , her property would be devolved upon your father , you and brother .

- Further , as you both have released their respective shares in favour of father , then father become singe owner of the property . 

- Your father can apply for getting mutation of the property in his name after submitting the mothers documents , released deed and death certificate of your mother. 

Yes,Definitely your father is absolute owner of the property aa per the facts of the case in the present matter. 

Release deed cannot be considered as a title deed,

The original sale deed in the name of your mother read with Release deed in favour of your father become the complete title deed.  After the death of your mother, your father, you and your brother became co-owner to the extent of 1/3rd share each.   You and your brother released 2/3 rd share in favour of your father.   The share of your father i.e. 1/3rd share vests in the original sale deed and release deed transfer only 2/3rd share.   Hence, release deed is title for 2/3rd share and is not title for the entire property.   Original sale deed with release deed confer complete title in favour of your father.  I hope you must have understand now.

On the execution of Release Deed relinquishing your individual undivided share in favour of your father by two of you in the jurisdictional Sub Registrar's Office, then based on this your father would have become Absolute Owner of the property. Hence Registered Release Deed has become part of the title to the property.

Not completely a title deed but proof of your share in the same

The release deed if executed by  a registered document shall be an indication that the other legal heirs have relinquished their rights in the property in favor of the existing shareholder.

After this your father should apply for mutation of revenue records with the revenue department and also apply for transfer of all the records to his name, he can be considered as an absolute owner with clear and marketable title only after completing all the said formalities.

Release deed is not a title deed.

The property will be transferred in your father's name on the basis of the release deed. But for that a suit has to be filed.

release deed is a legal document that removes the claim of a person from an immovable property and transfers his/her share to the co-owner.Release deed is not a title deed. 

Dear Sir/Madam,

You are suggested that the said release can't be termed as the titled deed and the same will be prepared at registrar's office in favor of father. 

No, release deed cannot be considered as title deed

Yes release deed can be considered as title deed combined with legal heir certificate and title deed of deceased owner.